Syringe



July 31, 1956 w. FERGUSON 2,756,748

SYRINGE Filed Jan. 5, 1952 IN V EN TOR.

Unite States Patent SYRINGE Garwood W. Ferguson, Paterson, N. J., assiguor to Becton, Dickinson and Company, Rutherford, N. J., a corporation of New Jersey This invention relates to a structurally and functionally improved hypodermic syringe.

It is an object of the invention to furnish an assembly of this character which may be constructed of any proper material and as such include a desirable grouping of parts. The assembly will lend itself ideally to the formation of a syringe from plastic and especially plastic as identified under the trade name of nylon. As such it will be feasible to produce an apparatus which Will be sold at a relatively nominal figure; the syringe functioning in all respects to provide an eminently satisfactory apparatus from the physicians or other users viewpoint.

An additional object is that of providinga unit of this type which may readily be manufactured by quantity production methods and by relatively unskilled labor; the parts of said assembly being capable of ready association with each other to furnish a unitary apparatus operating over long periods of time with freedom from all difficulties.

With these and other objects in mind reference is had to the attached sheet of drawings illustrating practical embodiments of the invention in which:

Fig. 1 is a sectional side view of the parts of the plunger and showing the same in disassembled condition;

Fig. 2 is a sectional side view showing these parts in assembled position and disposed in operative relationship with respect to a syringe barrel;

Fig. 3 is a view similar to Fig. 2 but showing an alternative structure;

Fig. 4 is a transverse sectional view taken along the lines 44 and in the direction of the arrows as indicated in Fig. 3;

Fig. 5 is a sectional side view of a further plunger assembly; and

Fig. 6 is a fragmentary sectional view of a still further structure.

Primarily referring to Figure 2, the numeral 10 indicates the barrel of the syringe. This barrel is preferably formed of nylon; it being obvious that other materials and plastics may also be employed. In the production of this unit ordinary and accepted techniques may be resorted to. The rear end of the barrel is open and preferably has extending from its edge zone a flange portion 11 of suitable configuration. The entrance to the barrel bore may be defined by a flared surface 12. The outer or forward end of the barrel is closed by a wall 13 from which a needle mounting tip 14 extends. The latter may involve any desired surfaces for cooperation with the needle hub (not shown). However, the tip should be provided with the usual passage or bore 15.

Referring particularly to Fig. 1 the plunger is also formed of any desired material, although in accordance with the present teachings it is of a plastic which conveniently may be identical with the material of the barrel. This plunger as illustrated may include a tubular body 16, the rear end of which defines a flange 17. As shown it is apparent that a suitable closure might be applied to seal the end of the plunger so as to protect and retain ele- See ments (such as one or more needles) within the plunger. If desired the plunger might, of course, be solid with 1ts rear end surface concave or ridged to be properly engageable by the thumb.

In any event the outer end of the plunger terminates 1n a solid portion the forward face of which is defined by a recess providing a threaded bore portion 18, the outer end of which may be defined by an enlarged unthreaded surface 20. A retaining member conveniently includes a threaded stem 22 to cooperate with the threads 18. A surface 23 may be provided forwardly of the threads 22 and mates with surface 20. A mounting portion 24 extends beyond the threaded part 22 and a head portion 25 may provide the outer end of this member. That head portion conveniently has a diameter equal to that of the plunger 16. The width of mounting portion 24 is substantially equal to the cross sectional diameter of an O-ring 26, although it might be more or less than such dimension. The ring may have an internal diameter equal to that of the mounting surface 24. The external diameter of ring 26 is slightly greater thanthe outer diameter of plunger 16.

Therefore, if the elements are constructed in this manner, ring 26 will be supported substantially against movement with respect to the parts of the plunger if the stem of member 22-25 is threaded through the opening of the ring and mounted by the plunger body. So mounted,

the inner end of stem 22 should clear the base of recess 18 v with the inner face of portion 24 engaging the outer end of body 16. This arrangement of the parts has been shown in Fig. 2. It is, of course, obvious that by suitably proportioning the parts, O-ring 26 would be capable of having limited movements in axial or radial directions with respect to the plunger assembly. In most instances it has been found, however, that either of such movements is unnecessary and in fact, undesirable, having in mind that the outer ring edge will sealingly engage the barrel bore.

In any event, with the plunger projected into that bore,

it is apparent that a proper sealis furnished. Such seal permits not alone of medicament being ejected through passage 15, when the plunger is projected, but also allows of an aspirating action when the plunger is retracted with respect to the barrel body. For purposes of illustration, the clearance between the plunger and the barrel bore has been exaggerated as has also the amount that ring 26 extends beyond the face of the plunger. It will be appreciated due to the flaring portion 12 and the rounded surface connecting it with the barrel bore, no difficulty will be experienced in introducing the forward end of the plunger into the barrel. The O-ring 26 is preferably formed of smooth-surfaced rubber or similar material. Its face may be coated with a light film of silicone grease. This will assure a smooth plunger action without any tendency of the parts to adhere. The sealing effect will not be impaired because the circular configuration of the ring 26 will not be distorted in view of the manner in which it is conveniently associated with the mounting member and the latter then applied to the plunger. Accordingly, no difficulties will be experienced incident to forcing the ring over the head portion 25 in order to mount the same. Separable plunger parts are ordinarily desirable in that they permit of ready grouping and disassembly without excessive wear on the O-ring, a ready cleaning of the latter, the mounting surface therefor an the adjacent parts.

It is apparent as in Figures 3 and 4 that if desired the barrel 27 might have its end Wall formed with an enlarged bore 29 conveniently tapered in an inward direction. That bore could receive a correspondingly tapered plug 30 formed with a head portion 31 and mounting a cannula 32. Plug 30 as shown, would conveniently be formed of a material similar to or identical with the material providing the plunger and barrel. Under certain conditions a structure such as'this may be more economically produced and/or will" provide a more satisfactory assembly. Also as shown in this view the head portion of the mounting member could conveniently be formed with a recess 28 corresponding to a screw-head slot, although such a recess is to be avoided when practicable. Where used, this slot would receive a suitable tool for tightening or releasing the mounting member with respect to the plunger.

Alternative types of mounting for the O-ring could also be obviously provided. Thus, as in Figure 5, the numeral 33 indicates the body of the plunger which in that exemplification is formed with a solid end wall 34 terminating in a reduced mounting portion or surface 35. Beyond this a screw threaded extension could be provided. Surface 35 would receive a ring 37 corresponding to ring 26. A threaded cap member 38 is mounted upon extension 36 and when in final position serves to support the ring 37 against undesired movements with respect to the plunger 33.

If a solid plunger 39, as in Fig. 6 is employed, then the ring mounting groove may include an outwardly bevelled surface 40. Beyond this an integral head portion 41 may be provided. Due to the surface 40, ring 42 may be readily removed when necessary.

Thus, among others, the several objects of the invention as specifically aforenoted are achieved. It is obvious that numerous changes in construction and a rearrangement of the parts might be resorted to without departing from the spirit of the invention as defined by the claims.

I claim:

1. In a plunger assembly for a hypodermic syringe in combination a mounting member presenting an end surface, a retaining member presenting a face to be disposed adjacent and spaced from said end surface, a mounting portion interposed between said face and surface and forming a part of one of said members, a sealing ring circular in section-disposed upon said mounting portion, said ring having a diameter greater than that of said members and being interposed between and engaged at diametrically opposite points by said face and surface respectively, said plunger having a bore adapted to store a hypodermic needle and the end of said plunger opposite said retaining member being provided with a closure for said bore and means to adjustably and fixedly support said retaining member upon the end of said mounting member.

2. In a plunger assembly for a hypodermic syringe in combination a mounting member presenting an end surface, a retaining member presenting a face to be disposed adjacent and spaced from said end surface, a mounting portion interposed between said face and surface and forming a part of one of said members, a sealing ringcircular in section-disposed upon said mounting portion, said ring having a diameter greater than that of said members and being interposed between and engaged at diametrically opposite points by said face and surface respectively said plunger having a bore adapted to store a hypodermic needle and the end of said plunger opposite said retaining member being provided with a closure for said bore, the end of said mounting member being formed with a threaded bore, a correspondingly threaded stem forming a part of said retaining member and disposed within said bore to adjustably and fixedly retain said memberswith respect to each other and said mounting surface being included as part of said retaining member.

3. In a plunger assembly for a hypodermic syringe in combination a mounting member presenting an end surface, a retaining member presenting a face, a mounting portion interposed between said face and surface and forming a part of one of said members, a sealing ring circular in section-disposed upon said mounting portion, said ring having a diameter greater than that of said members and being interposed between and engaged at diametrically opposite points by said face and surface respectively said plunger having a bore adapted to store a hypodermic needle and the end of said plunger opposite said retaining member being provided with a closure for said bore, said mounting portion forming a part of said mounting member, a threaded extension also forming a part of said mounting member and disposed beyond said mounting portion and said retaining member being in the form of a collar formed with a threaded bore to receive said extension and thus be adjustably and fixedly supported adjacent the end of said mounting member.

References Cited in the file of this patent UNITED STATES PATENTS Hein Aug. 7, 1928 812,686 Schork et a1. Feb. 13, 1906 1,687,091 Nelson Oct. 9, 1928 1,771,219 Hein July 22, 1930 2,575,425 Nelson Nov. 20, 1951 2,629,376 Gallice et a1. Feb. 24, 1953 I FOREIGN PATENTS 2,164 Great Britain June 15, 1901 4,706 Austria July 25, 1901 5,189 Great Britain Apr. 23, 1903 19,848 Great Britain July 24, 1913 749,995 France Aug. 2, 1933 

